A prior art shoulder rest is described in German patent application No. DE-AS 26 04 897 which was published Aug. 19, 1976 by the German Patent Office. This shoulder rest consists essentially of the clamping devices for supporting the string instrument and the support plate itself. The support plate is a two-piece construction displaying on one side a relatively thick padding plate which contacts the person playing the instrument, and on the other side a bearing plate consisting of a thin metal plate that supports on one of its two sides the clamping devices, and is secured on its other side to the padding plate. By bending the thin metal bearing plate, adaptations of the supporting plate to the particular body shape of the person playing the instrument are possible.
However, this type of prior art shoulder rest can only be fitted to a limited extent to the body shape of the person using the instrument, and it enables only a limited extension of one clamping device along the longitudinal axis of the shoulder rest. With such a construction, supporting a viola is not possible.
The problems with the prior art which are overcome by the present invention include increasing the width of adjustment of the clamping devices that hold the instrument itself upon the rest, and allowing adjustment of the flexibility and, in particular, the degree of pliableness of the actual support plate.